1. Field of the Invention
The invention relates to a flywheel device, and more particularly to a flywheel device for motor vehicles.
2. Description of the Related Art
German reference DE GM 94 14 314, especially in FIG. 2 thereof, teaches a flywheel device in which a grease chamber is formed in an output-side centrifugal mass that serves to accommodate an internal gear, planetary gears and a sun gear attached firmly to a drive-side centrifugal mass. The aforementioned toothed gears constitute load-transmitting elements of a planetary gear system. At least one of the elements, for example, the internal gear, is attached to the output-side centrifugal mass and is connected to the drive-side centrifugal mass via a spring assembly of a torsional damping device, which acts upon the planetary carriers, via the latter as well as the planetary gears and the sun gear. The planetary carriers form a rough seal for the grease chamber, while cover plates arranged on both sides of the grease chamber and connected to a ring that encompasses the chamber radially are used to attain a fine seal. Although the left cover plate in FIG. 2 of this reference extends radially inward over the meshing region of the internal gear/planetary gears, it does not extend all the way to the meshing region of the planetary gears/sun gear. Thus, viscous medium contained in the grease chamber, which is displaced in the axial direction between the tooth flanks of the sun gear and the planetary gears when these toothed gears roll upon one another, is able to emerge from the grease chamber through gaps formed between the planetary carrier associated with this cover plate and a friction device. Furthermore, due to the centrifugal force arising during operation of the flywheel device, the viscous medium can move radially outward in an axial fashion between the drive-side centrifugal mass and the adjacent cover plate, where, although it could possibly be held back by means of a friction ring, it nonetheless changes the frictional properties of the latter considerably. In any case, this sort of emergence of viscous medium from the grease chamber is undesirable, because when there is loss of the medium in the grease chamber, the damping properties of the medium in respect to the planetary gear system deteriorate.
DE 35 15 928 C2 describes another flywheel device with two centrifugal masses that are movable relative to one another. The output-side centrifugal mass accommodates a grease chamber, into which engages a load-transmitter in the form of a hub disk attached firmly to the drive-side flywheel mass. The grease chamber is sealed relative to the output-side centrifugal mass by an O-ring. Because this 0-ring must absorb all movements of the two centrifugal masses relative to one another, due to its frictional connection to the latter, it is subject to heavy wear.